performance - Execute bulk find queries with sorting and limit mongo -

i have documents contain category field , want take top 10 documents each category based on popularity, seniority , rise in popularity. plan on using votes field within document determine popularity, _id field seniority , votesperday field determine rising in popularity. there total of 12 categories.

typical documents this.

{    name : 'alpaca',    category : 'blue',    votes : 500,    _id : object.id,    votesperday : 50 }  {    name : 'muon',    category : 'green',    votes : 100,    _id : object.id,    votesperday : 20 } 

i have object needs store categories , within each category store popular, newest , rising in popularity. object refreshed every 24 hours.

where running trouble whenever want query mongo 12 different categories.

i have tried have loop run 3 queries each category , store results once arrive fails since seems on loading mongo server , crashes.

the architecture of object trying build this.

var myobj = {category1 : {     newest : [0,2....9],    mostpopular : [0,2....9],    risinginpopularity : [0,2....9]  } ..... 12 of such objects}; 

the way thought of performing queries (although bit uncomfortable doing way) was.

categories.foreach(function(category){       var query = {category : category}     var sort = //sorting criterion newest      performquery(query,sorting,function(results){        myobject[category].newest = results      });      sort = //sorting criterion popular  performquery(query,sorting,function(results){        myobject[category].mostpopular= results      });   sort = //sorting criterion rising in popularity  performquery(query,sorting,function(results){        myobject[category].risinginpopularity = results      });   //limit has set 10 documents   }); 

so question how best perform type of mass query need obtain documents based on category , retrieve top 10 documents have votes, added (based on _id), , have votesperday.